Install libkarel from PyPI (#9)

This change uses the PyPI wheel instead of just copying the .py file
from GitHub.  #minor

Author: lhchavez

Dockerfile.rootfs

@@ -16,7 +16,7 @@ RUN rm packages-microsoft-prod.deb
 RUN apt-get update -y && \
     apt-get install --no-install-recommends -y \
       clang-10 \
-      dotnet-sdk-3.1 \
+      dotnet-sdk-3.1=3.1.401-1 \
       fp-compiler-3.0.4 \
       fp-units-fcl-3.0.4 \
       g++ \

args.cpp

@@ -453,7 +453,7 @@ bool Args::SetCompileFlags(std::string_view root,
       return false;
     program_args_holder = {
         "/usr/share/dotnet/dotnet",
-        "/usr/share/dotnet/sdk/3.1.301/Roslyn/bincore/csc.dll",
+        "/usr/share/dotnet/sdk/3.1.401/Roslyn/bincore/csc.dll",
         "-noconfig",
         "@/usr/share/dotnet/Release.rsp",
         StringPrintf("-out:%s.dll",

tools/mkroot

@@ -15,6 +15,7 @@ import tarfile
 import tempfile
 import textwrap
 import urllib.request
+import zipfile
 from typing import Any, Dict, List, Optional, Sequence, Set, Union
 
 import apt
@@ -600,7 +601,7 @@ def _main() -> None:
                 root.copyfromhost(filename)
 
         with RemoteFile(
-                'https://raw.githubusercontent.com/omegaup/libkarel/master/libkarel.py',
+                'https://raw.githubusercontent.com/omegaup/libkarel/v0.0.99/libkarel.py',
                 '9b67427877bb8ba5bbf3bbde9dcf828c81d3f2cd') as remote_file:
             root.install('/usr/lib/python2.7/libkarel.py', remote_file.path)
 
@@ -615,9 +616,24 @@ def _main() -> None:
                 root.copyfromhost(filename)
 
         with RemoteFile(
-                'https://raw.githubusercontent.com/omegaup/libkarel/master/libkarel.py',
-                '9b67427877bb8ba5bbf3bbde9dcf828c81d3f2cd') as remote_file:
-            root.install('/usr/lib/python3.8/libkarel.py', remote_file.path)
+                'https://files.pythonhosted.org/packages/97/20/a73731474363a3998d7b9097632be23ab17c4ad551aea4f1234fd964e524/libkarel-1.0.2-py3-none-any.whl',
+                '1585263c50bf3956350fd617258b48ca05013776') as remote_file:
+            with zipfile.ZipFile(remote_file.path) as z:
+                z.extractall(os.path.join(PYTHON3_ROOT, 'dist-packages'))
+        logging.info('Precompiling libkarel.')
+        subprocess.check_call([
+            '/usr/bin/python3',
+            '-m',
+            'py_compile',
+            os.path.join(PYTHON3_ROOT, 'dist-packages/libkarel/__init__.py'),
+            os.path.join(PYTHON3_ROOT, 'dist-packages/libkarel/libkarel.py'),
+            os.path.join(PYTHON3_ROOT, 'dist-packages/libkarel/kareltest.py'),
+        ])
+        root.copyfromhost(os.path.join(PYTHON3_ROOT, 'dist-packages/libkarel'))
+        root.copyfromhost(
+            os.path.join(PYTHON3_ROOT,
+                         'dist-packages/libkarel-1.0.2.dist-info'))
+        logging.info('Done.')
 
     with Chroot(
             os.path.join(args.target, 'root-ruby'), RUBY_ROOT,